This application claims the benefit of the Korean Patent Application No. 10-2005-122474, filed on Dec. 13, 2005, which is hereby incorporated by reference as if fully set forth herein.
1. Field of the Invention
The present invention relates generally to control apparatuses for engine-powered forklifts and, more particularly, to a control apparatus for an engine-powered forklift which is constructed such that, when the forklift is in a working mode, the output of an engine is allowed to be increased higher than a preset output value, and, when the forklift is in a traveling mode, the output of the engine is restricted to the preset output value to restrict the traveling speed of the forklift.
2. Description of the Related Art
As well known to those skilled in the art, an engine-powered forklift has an engine, a hydraulic pump, and actuators. The hydraulic pump is driven by the engine, so that the forklift travels and turns. The actuators are operated by using hydraulic oil discharged from the hydraulic pump.
Furthermore, the engine-powered forklift can travel and turn with loading a heavy cargo thereon. However, if the traveling speed of the forklift, on which the cargo is loaded, is excessively high, the cargo may undesirably fall down, or the forklift may tip over. Furthermore, in the case where the forklift is operated at a relatively high speed in an indoor place, for example a warehouse, there is a possibility of a safety hazard in which it may strike a person.
In an effort to overcome the above problems, an apparatus that restricts the traveling speed of a forklift from increasing higher than a predetermined speed was proposed.
The conventional traveling speed restriction apparatus for the forklift includes a stopper. The stopper of the conventional restriction apparatus is disposed below an accelerator pedal and prevents the rotation of the accelerator pedal beyond a predetermined position, when the accelerator pedal is pushed. Therefore, the output of an engine is prevented from being increased to a value higher than a preset output value. Thereby, the traveling speed of the forklift is restricted to the specified speed.
However, the conventional traveling speed restriction apparatus is problematic in that, because the output of the engine is restricted to the preset output value, the driving force of an actuator is also restricted.
In detail, due to the characteristics of the engine-powered forklift, when the actuators are operated for tilting a mast assembly or lifting a carriage with loading the heavy cargo, the accelerator pedal must be pushed beyond the predetermined position in order to increase the output of the engine for ensuring smooth and powerful operation. However, in the conventional traveling speed restriction apparatus, because the distance that the accelerator pedal is pushed is restricted, the output of the engine cannot be increased higher than the preset output value.
As such, because the output of the engine cannot be increased higher than the preset output value, the driving force of the actuator is restricted. Due to the restriction of the driving force of the actuator, there are problems in that the mast assembly cannot be smoothly tilted, and the carriage cannot be smoothly lifted.